This application relates to retro-reflective road markers for installation on the pavement of a road.
Road markers having retro-reflective lenses are used on road surfaces to delineate lanes at night. The road markers reflect light from the headlights of an automobile at night to indicate where the lanes of a road are positioned. The markers typically have a trapezoidal cross-section with a rectangular bottom. These markers are approximately two inches wide by four inches long and three-quarters of an inch high. The markers are mounted directly to the road with suitable materials such as bituminous or epoxy.
The markers typically include a molded plastic shell which has cube corner reflective surfaces. These surfaces are formed on the inside of the shell and plated with metal, preferably aluminum. The shells are then filled with a potting material, such as a mixture of epoxy, to provide strength. The potting material provides the marker with strength to withstand the weight of large vehicles such as trucks.
Recently, it has been found that the reflectivity of potted reflectors is decreased over time by transmigration of asphalt chemical tar from the road surface and of the bituminous material used to affix the markers to the road to the metallic coating on the inside of the shell. Thus, it is desirable to provide a marker which is economical, strong and which will resist transmigration.
The invention relates to a potted road marker and method for making the road marker. The road marker includes a reflective member and a base member which is formed about the end portions and a bottom to encapsulate portions of the reflective member. The reflective member includes a shell having a top and two sides which extend between a pair of ends. At least one of the sides is formed with cube corners which are metallized. The top, sides and ends define a cavity which is filled with a potting material such as epoxy. Each end of the marker has an extended portion which extends longitudinally outwardly. The base member has a lower platform portion having two projections which extend upwardly from the top surface of the base. The projections are spaced apart to receive the reflective member thus between. The projections are wider and slightly higher than the reflective member. The end projections have a curved surface extending from the top to the base so that the projections protect the ends of the reflector. The base is molded about the previously formed reflective member so that the ends of the reflective member are encapsulated in the projections of the base member. In this way, each reflector is securely held to the base and permanently mounted to the base member. Additionally, the base of the reflector member is encapsulated in the base member to prevent transmigration of bituminous or tar chemical into the reflective member.